1. Field of the Invention
The present invention relates to environmental test chambers, e.g. laboratory ovens, for subjecting electronic components to environmental extremes while the components are electrically energized and operating, and particularly to a method and apparatus for facilitating the insertion and ejection of the component trays in the connection and disconnection of component tray electrical connections to mating chamber wall mounted electrical connectors prior to commencement of and following completion of the environmental test of the components.
2. Description of the Prior Art
The design and use of environmental test chambers in which the operation of electrically energized components is tested is well known in industry. Thermal testing or "burn-in" of high reliability integrated circuits for military, aerospace, medical device and other high reliability applications has become institutionalized in the sense that military and industrial specifications for such components require that they survived rigorous thermal and, for certain applications, other environmental testing conditions. Consequently, thermal ovens and environmental test chambers are often employed in quality control and in receiving and inspection operations in manufacturing facilities and operations and they are also employed in research and development laboratories for the testing of new integrated circuit designs. In addition, components other than integrated circuits are often subjected to such testing for the same reasons.
A wide variety of bench top and cabinet environmental chambers and ovens have been developed and are marketed for such uses. Particular designs of "burn-in" ovens which have been developed and are marketed are large enough to simultaneously test manufacturing lots of micro-electronic integrated circuit (IC) devices. These devices are mounted into removable test trays which in turn are slidably suspended in spaced-apart lateral tray supports mounted inside the oven chamber, so that the trays are separated from one another to allow for even temperature distribution by air circulating within the chamber. The test trays are relatively flat and thin and can contain a number (such as 64 or 128) IC pin receptacles, into each of which an IC is inserted. The trays include printed circuit conductors leading from the receptacle terminals to an array of input and output signal terminals forming a tray connector which is usually located on one end of the rectangular tray. The tray connectors of the trays inserted into the rack of lateral supports thus face the rear wall of the chamber. The rear panel of the chamber is usually constructed to be removable and adapted to be fitted with an array of spaced apart mating connectors for receiving the tray connectors of the trays mounted in the rack or racks. The rear panel connector array may be connected to a test circuit for supplying signals to and receiving signals from the IC components under test. Such burn-in ovens are typified by the model PBC 2-32 burn-in oven and other ovens sold by Despatch Industries, Inc.
Such high capacity temperature and other environmental chambers designed for micro-circuit manufacturing facilities are used on a continuous basis for conducting burn-in testing and other environmental testing of manufacturing lots. Manufacturing personnel are required to manually load and unload the trays frequently enough during an operating shift that errors may arise from time to time in making an electrically complete connection of all the tray connectors with all the panel mounted connectors. A certain amount of force must be employed to push each tray connector into its mating panel mounted connector during the insertion operation and pull it out in the ejection operation. The mating male and female terminals are precisely dimensioned with close tolerances in order to achieve an adequate electrical connection each time a connection is made. Moreover, the connectors must withstand repeated connect and disconnect operations as well as the temperature and other environmental extremes encountered in the oven or environmental test chamber. Consequently, it takes a fair amount of force to connect the connectors together and to break the connection to remove the trays on completion of a test. Such repetitive effort is fatiguing to operators, particularly in high capacity manufacturing operations.
A need thus exists for a method and apparatus for facilitating the insertion of the tray connectors to make an electrical connection with the panel mounted connectors. A need exists for an automated apparatus for inserting and ejecting the trays to relieve operators from the effort of manually making and breaking the electrical connections and for ensuring that consistent forces are achieved during insertion and ejection.